ElectricityW. and R. Chambers, 1866 - 273 pagina's |
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Veelvoorkomende woorden en zinsdelen
action armature attraction axis B. A. unit ball bismuth body brass Bunsen cell cable cell charge chemical circuit conducting power connected copper wire cubic centimetres current electricity current passes cylinder deflection direction discharge distance earth effect electric machine electro-magnet electro-motive force Faraday fixed fluid frictional electricity galvanic battery galvanic pair galvanometer gives glass ground gutta-percha heat hydrogen inches induced current induction insulated knob length Leyden jar liquid magnetic meridian magnetic needle magnetised magneto-electric metal metre molecules motion move nitric acid non-conductors north magnetic pole north pole opposite electricities outer coating oxygen particles pendulum plane plate platinum polarised polarity position primary coil prime conductor quantity repelled resistance rheostat ring rotation rubbed shell-lac shewn in fig shews soft iron south pole spark station strength sulphuric acid supposed surface takes place tangent galvanometer telegraph tension theory thick tion tricity tube vertical wire zinc
Populaire passages
Pagina 3 - A magnet has, then, two poles or centers of magnetic force, each having an equal power of attracting iron. This is the only property, however, which they possess in common, for when the poles of one magnet are made to act on those of another, a striking dissimilarity is brought to light. To show this, let us suspend a magnet, N 8, fig.
Pagina 264 - With a machine that consumes carbons half an inch square, a light of such intensity is got, that when put on a lofty building it casts shadows from the flames of street-lamps a quarter of a mile distant upon the neighbouring walls.
Pagina 181 - This consists (fig. 17) generally of a round bar of soft iron bent into the horseshoe form, with an insulated wire coiled round its extremities. When a current passes through the coil, the soft iron bar becomes instantly magnetic, and attracts the armature with a sharp click. When the current is stopped, this power disappears as suddenly as it came. Electro-magnets far outrival permanent magnets in strength. Small...
Pagina 36 - At twelve at night, the magnet is 1|, east of the mean position, and continues nearly in the same position, with only a slight westerly deviation, till 15 hours (three in the morning), when it veers eastward. At 20 hours (eight in the morning), it reaches its furthest east point. From eight in the morning till one in the afternoon, it makes a sweep of 10' towards the west, and then stands about 6
Pagina 240 - S (fig. 131), and sets the clock-work in motion, and sends back to S that he is ready, and the printing thereupon begins. When both keys are depressed, the whole circuit is broken, so that when both sender and receiver have their hands on their respective keys no message can be sent.
Pagina 181 - When the bar is thinner than one-third of an inch, a maximum is soon reached beyond which additional turns of the wire give no additional magnetism; and even when the core is thick, these turns must not be heaped on each other, so as to place them beyond influencing the core. It follows from the above principle, that, in the...
Pagina 94 - Fig. 59. handle. These plates are accurately ground, the one to the other, so that when placed upon each other they touch in every part. Their inner surfaces are covered with a very thin and equable layer of shell-lac.
Pagina 234 - A perpetual rotation is in this way kept up. The manner in which a constant rotary motion may be obtained by electro-magnetism being understood, it is easy to conceive how it may be adapted to the discharge of regular work. Powerful machines of this kind have been made with a view to supplant the steam-engine ; but such attempts, both in respect of economy and constancy, have proved utter failures.
Pagina 104 - ... the unconducting dry earth, and, in consequence, strikes off to a part of the ground where it may easily disperse itself and be lost. Wherever it is practicable, a lightning-conductor should end in a well or large body of water. Water is a good conductor, and having various ramifications in the soil, offers the best facility to the electricity to become dispersed and harmless in the ground. The rod on reaching the ground should be...
Pagina 95 - ... their parallelism on removal. This last is of the utmost importance ; and it is found, where numerical results are wanted, that little dependence can be placed on the parallelism attained by the hand. For more accurate observations, the C. is made quite separate from the electrometer. The plates are in this case attached vertically to two wooden pillars, on which they are insulated, and which slide in a horizontal groove made in the sole of the instrument. The plates, thus guided by the grooves,...